Make crust: In a food processor blend together flour, sugar and butter until mixture resembles coarse meal. Add 2 tablespoons water and toss until incorporated. Add enough remaining water if necessary until mixture comes together but is still crumbly. Refrigerate dough, wrapped in plastic, for one hour.

Press evenly onto bottom and sides of an 11 inch tart pan with removable fluted rim. Prick the crust with a fork, line the dough with aluminum foil and weigh it down with pie weights or beans and bake in the middle of oven until golden brown, about 30 minutes.

Make filling while crust bakes: In a bowl with an electric mixer beat together cream cheese, sugar, vanilla, and egg until smooth. Add flour and blend mixture well.

Pour the filling into the warm crust, spreading evenly and bake in middle of oven until set, about 20 minutes. Cook the tart in its pan on a rack.

In a small saucepan heat jam with water over moderate heat, stirring until melted and smooth. Remove pan from heat and cool jam slightly. Arrange raspberries (blueberries can also be used) decoratively on top of tart and brush gently with jam.